Selected 2-arylimino-4-hexafluoroisopropylidene-1, 3-dithietanes and their preparation



United States Patent SELECTED 2 ARYLIMJNO 4 HEXAFLUOROISO- PROPYLIDENE-1,3-DITH1ETANES AND THEIR PREPARATION Maynard S. Raasch, Fairfax, Del., assiguor to E. I. du Pont de Nemonrs and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed Sept. 28, 1964, Ser. No. 399,880

12 Claims. (Cl. 260-152) ABSTRACT OF THE DISCLOSURE Claimed are certain .2 arylimino 4 hexafiuoroisopropylidene 1,3 dithietanes, e.g., 2 (phenylimino) 4 [2,2,2 trifluoro 1 (trifluoromethyl)ethy1idene]- 1,3 dithietane and 2 (p phenylazophenylimino) 4- [2,2,2 trifluoro 1 (trifiuoromethyl)ethylidene] 1,3- dithietane, useful as textile-treating agents such as antistatic agents for W001. They may be prepared by reacting, at a temperature in the range of 20 to 150 C., bis(trifluoromethyl)-thioketene with. an appropriate aryl isothiocyanate, e.g., phenyl isothiocyanate and p-phenylazophenyl isothiocyanate.

FIELD OF THE INVENTION This invention relates to, and has as its principal objects provision of, novel fluorinated 1,3-dithietanes and a preparation of the same.

DESCRIPTION OF THE INVENTION The new products of this invention are 2-ary1imino-4- hexa fluoroisopropylidene 1,3 dithietanes of the general formula where m is a whole number from 1 to v2; Ar is 1- to 3-ring arylene; X is halogen, lower alkyl, lower hydrocarbyloxy in which any unsaturation is ethlyenic, 1- to 6-carbon carbacyl, phenylazo, nitro or lower carbalkoxy; and n is a whole number from 0 to 3.

These products are prepared by reacting, at a temperature in the range of 20 to 150 C., bis(trifluoromethyl) thioketene with an aryl isothiocyanate of the formula S=C=N AI Xn Jm where m, Ar, X and n have the previously stated significance. The reaction is represented by the equation:

cyanate. These are well-known compounds prepared by standard methods.

The reaction between bis(trifluoromethyl)thioketene and the aryl isothiocyanate proceeds at relatively low temperature, of the order of 20 C. More practical reaction rates are obtained at somewhat higher temperatures, of the order of 50 C. However, there is no advantage in exceeding about 150 C., and the preferred range of temperature is that between 50 and 110 C. Within this range, substantial conversions are obtained in a short time, e.g., 1-2 hours, and it is generally unnecessary to prolong the reaction time beyond about 20 hours. Since bis(trifluoromethy1)thioketene boils at 53 C., operation above this temperature is best carried out in a closed vessel under the autogenous pressure developed by the reaction components. However, it is also possible to pass the reactants at or near atmospheric pressure through a reaction zone, such as a tube, heated to the desired temperature.

The reaction may be carried out in the absence of a solvent. When the isothiocyanate reactant is a solid, it is convenient to use a nonreactive solvent such as a hydrocabron or halogenated hydrocarbon. Examples of suitable solvents are n-hexane, cyclohexane, benzene, toluene, dichloromethane, carbon tetrachloride, dichlorotetrafiuoroet-hane, 1,1,2 trichloro 1,2,2 trifluoroethane, chlorobenzene, and the like.

The relative proportions of the two reactants are not critical, as the reaction will proceed regardless of what they are. As a matter of convenience, approximately equimolar amounts are normally used, i.e., one mole of bis(trifluoromethyl)thioketene for each isothiocyanate group present in the aryl isothiocyanate, but an excess of one or the other reactant, particularly bis(trifluoromethyl) thioketene, can be employed.

Occasionally, minor amounts of the bis(trifiuoromethyl) thioketene may dimerize or polymerize under the operating conditions. If present, these by-products can be readily removed. The dimer can be sublimed out under reduced pressure, and the polymer, which is insoluble-in most organic solvents, can be separated by solvent extraction. The dithietane reaction products are solids which can be purified, if necessary, by crystallization from an appropriate solvent.

EMBODIMENTS OF THE INVENTION There follow some nonlimiting examples which illustrate the invention in more detail.

EXAMPLE 1 2-(phenylimin0)-4- [2,2,2-triflu0ro-1-(trifluoromethyl) ethylidene] -1,3-dithietane Equimolar quantities of phenyl isothiocyanate and his- (trifluoromethyhthioketene were heated at C. in a sealed glass vessel for 15 hours. On cooling to room temperature, the product crystallized. It was filtered from liquid present and recrystallized from methanol to give a 49% yield of the white dithietane, MJP. 4647 C.

Analysis.-Calcd forC H F NS C, 40.16; H, 1.53; S, 19.50. Found: C, 40.10; H, 1.66; S, 19.46.

In confirmation of the structure, the F nuclear magnetic resonance spectrum shows a singlet, which indicates the two CF groups are equivalent, and the infrared spectrum has a band at 6.15 assigned to the exocyclic C=C bond.

3 EXAMPLE 2 '2- (p-chlarophenylimino) -4- [2,2,2-trifluro-1-(trifluoromethyl ethy l i dene] -1 ,S-diIhietane Equ m unt of po pheny so h qsy uate n i it ifl or m thy h o sn o e e with 00 m1.-

2- (3,4,5-trimethoxyphenyZimino) -4- [2,2,2-triflu0r0-1- trz'fluoram et-hyl ethyl idene] -1,3-dithietane 3,4,5-trimethoxypheny1isothiocyanate (1 mole) and'his- (trifluoromethyl) thioketene (3 moles) weresealed in a glass vessel and heated at 100 C. for 16 hours. The cooled product was stirred with dichloromethane and filtered to remove polymer. The filtrate was evaporated and the residue was-recrystallized from hexane to give a 73% yield of the white dithietane, M.P. 89.7-90.5 C.

Analysis.-.Calcd for C14H11F2NO3S2 C, H2 2.-64; S, 15.29. Found: C, 40.84;"H, 2.76; S, 15.33.

The F nuclear magnetic resonance spectrum consists of a singlet.

The 3,4,5-trimethoxypheny1isothiocyanate was made by adding 3,4,5-trirn ethoxyaniline to a stirred, aqueous suspension of thiophosgene. After recrystallization from hexane, the product melted at 66 C.

EXAMPLE 4 2- (p-phenylazopherrylim in0).-4- [2,2,2-trifluoroJ-(trifluoromethyl ethy lidene] -1,3-dithietane C33 S C=C C=N N=N@ C63 \S/ Equimola-r amounts of p-phenylazophenyl isothiocyaat (Bolser and Ha sh m J- em- Soc, 5, 23.49 (1923)) and bis (trifiuoromethyl)thioketene, togetherwith four moles of dichloromethane as solvent, were heated in a sealed glass vessel at 100 C. for 16 hours. The isothiocyanate was not completely used up because part of the thioketenehad been converted to its dimer. The solvent was allowed to evaporate and the dimer was sublimed off. The residue was then heated with another molar quantity of bis (trifluoromethynthioketene for 16 hours. Dimer of the thioketene was sublimed out under vacuum at 100 C. and the product remaining was recrystallized from ethanol; yield, 71%, M.P. 118-119" 0., orange crystals.

, Analysis...-Calcd for C H F N S C, 47.11; -H, 2.09; S, 14.80. Found: C, 47.01; H, 1.82; S, 14.92.

The F nuclear magnetic resonance spectrum consists ot a sing fit.

' EXAMPLE methyl) ethylidene] -1,3-dithietane CFs S =0 0: 'Fa S Equimolar amounts of l-naphthyl isothiocyanate and his (trifluoromethyl) thioketene were heated at C. in a sealed glass vessel for 15 hours. The product was recrystallized from dichloromethane-ethanol to give a 79% yield of the white dithietane, M.P. 128.5-128.7 C.

Analysis.Calcd for C 5l7I-1E NS C, 47.49; H, 1.86; S, F und; C; -2 ;'H,.1,.6. .7-32

.The F nuclear magneticresonancespectrum-consists of a singlet.

The foregoing-detailed examples illustrate, the prep aration of specific'products of this invention. Application of thedcscrihe prqcedureto other, aryliisothiocyanates yields in a similar manner other 2- arylimino-4-hexafluoroisopropylidene-1,3-dithietanes of the structure defined in the general formula previously set forth. Additional examples of specific products of this invention areugivenjn the table below. The first column lists by name the aryl isothiocyanate (mono-or diisothiocyanate) reactedwith the b i s(trifluoromethybthioketene. Opposite eachname, the second column shows the formula of the -Ar'X' gr oup present in the resulting, dithietane of general formula oF, 2c=o 1=.1-I--iurXn S m Thenumber m will always be 1 except-when'the reactant in the first column is a diisothiocyanate, in which case m is 2.

TABLE lsothioeyanate Ar-Xr1 in Reaction Product.

o-Tolyl p-Butylphenyl p-Butoxyphenyl (lingo-- p-Allyl mhenyl m=cu-ouio- I p-Phen xyphenyl CaH5O- p-Aeetr em 3 p-Benzoylphenyl C H C0 TABLEContinued Isothiooyanate .Ar-Xu in Reaction Product p-Fluorophenyl F I 2,4-dibromopheny1 Br I 3,4dichlorophenyl C 1Q- I 3-bromo-p-tolyl C EEG- N (I) 3 H 3 nitro-o-tolyl 4-fluoro-3-nitrophenyl 4-carbomethoxypheny1 c1130 0 0- (J 0 0 C zHs B-carbethoxyphenyl 4-carbobutoxyphenyl 0 H90 0 OG- p-Phenylenediisothiocyanate 2,4-tolylenediisothiocyanate.-.

The compounds of the present invention are useful as textile-treating agents, such as antistatic agents for W001. Strips of wool fabric were dipped in 1% solutions in dichloromethane of the compounds of each of the examples and dried. The strips were next laid on a glass surface and stroked with a plastic rod in a standard manner. The strips were then held in a vertical position and the attraction, or lack thereof, to the glass rod was noted. The attraction of the treated strips to the rod was greatly reduced or nearly eliminated compared to an untreated control strip which was strongly attracted. This shows that much less static change was built up on the treated strips.

Since obvious modifications and equivalents in the invention will be evident to those skilled in the chemical arts, I propose to be bound solely by the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.

6 I claim: 1. A compound of the formula wherein m is a whole number from 1 to 2;

Ar is 1- to 3-ring arylene;

X is selected from the group consisting of halogen, lower alkyl, lower hydrocarbyloxy, in which any unsaturation is ethylenic, 1- to 6-carbon carbacyl, phenylazo, nitro and lower carbalkoxy; and

n is a whole number from 0 to 3.

2. 2 (phenylimino) 4- [2,2,2-trifluoro-l-(trifluoromethyl) ethylidene] -1,3 -dithietane.

3. 2 (p-chlorophenylimino) 4 [2,2,2-trifluoro-l- (trifluoromethyl) ethylidene] -1,3-dithietane.

4. 2 (3,4,5 trimethoxyphenylimino) 4-[2,2,2-trifluoro-l-(trifluoromethyl)ethylidene]-1,3-dithietane.

5. 2 (p phenylazophenylimino)-4-[2,2,2-trifluoro-l- (trifluoromethyl) ethylidene] -1,3-dithietane.

6. 2 (1 naphthylimino) 4 [2,2,2-trifluoro-1-(triflu0romethyl)ethylidene]-l,3-dithietane.

7. The process which comprises reacting, at a temperature in the range of 20 to C., bis(trifluoromethyl)- thioketene with an aryl isothiocyanate of the formula wherein m is a whole number from 1 to 2;

A1- is 1- to 3-ring arylene;

X is selected from the group consisting of halogen, lower alkyl, lower hydrocarbyloxy, in which any unsaturation is ethylenic, 1- to 6-carbon carbacyl, phenylazo, nitro and lower carbalkoxy; and

n is a whole number from 0 to 3.

8. The process which comprises reacting, at a temperature in the range of 20 to 150 C., bis (tn'fluoromethyD- thioketene with phenyl isothiocyanate.

9. The process which comprises reacting, at a temperature in the range of 20 to 150 C., bis (trifluoromethyl)- thioketene with p-chlorophenyl isothiocyanate.

10. The process which comprises reacting, at a temperature in the range of 20 to 150 C., bis(trifluoromethyl)- thioketene with 3,4,5-tri-methoxyphenyl isothiocyanate.

11. The process which comprises reacting, at a temperature in the range of 20 to 150 C., bis (trifluoromethyl)- thioketene with p-phenylazophenyl isothiocyanate.

12. The process which comprises reacting, at a temperature in the range of 20 to 150 C., bis (trifluoromethyl)- thioketene with l-naphthyl isothiocyanate.

No references cited.

WALTER A. MODANCE, Primary Examiner.

JAMES A. PATTEN, Examiner. 

1. A COMPOUND OF THE FORMULA 